Turbine Airfoil Spanwise Loading for Vortex Control
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Solution Overview
Problem
Turbine blades in gas turbine engines face challenges with vortex structures forming near the hub and tip sections, leading to reduced work transfer and thrust capability, and controlling these vortices is crucial for efficiency and structural integrity, especially in unshrouded blades where tip leakage flow complicates the aerodynamic and structural optimization.
Innovation Solution
The airfoil profile is designed with varying unguided turning (UGT) and stagger angles along the span length, optimized through a specific ratio (UGT:S = -0.48SL + 0.66 ± 0.1) to manage Mach numbers, suction surface pressure diffusion, and vortex growth, concentrating loading at the hub and tip regions to minimize losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional airfoil profiles are used with uniform loading distribution, then manufacturing is simpler, but vortex structures form near hub and tip sections reducing work transfer and thrust capability
Solution Approach 1:
The patent applies local quality by varying the airfoil profile geometry along the span length to create different loading characteristics at different locations. Specifically, the airfoil profile is designed with different camber distributions and thickness ratios at the hub section versus the tip section, allowing localized optimization of flow control and vortex suppression while maintaining overall blade performance.
Solution Approach 2:
The blade span is segmented into distinct regions (hub section, mid-section, tip section) with each region having optimized airfoil characteristics. This segmentation allows independent optimization of each section to address local flow conditions and vortex formation patterns, improving overall work transfer while managing complexity through modular design approaches.
2Loss of energy
If tip shrouds are added to control tip leakage flow, then vortex-related losses are reduced, but blade weight increases and structural complexity increases
Solution Approach 1:
The patent extracts the tip leakage control function from the traditional shroud structure and integrates it directly into the airfoil profile geometry at the tip section. By modifying the tip airfoil shape to include specific camber and thickness characteristics, the blade controls tip leakage flow without requiring additional shroud components, thereby reducing weight while maintaining energy efficiency.
Solution Approach 2:
The patent merges the tip leakage control function with the primary airfoil profile, combining what were previously separate functions (lift generation and tip leakage control) into a unified airfoil design. This integration eliminates the need for separate shroud structures while achieving both aerodynamic performance and leakage control.
3Loss of energy
If airfoil profile is optimized for hub region vortex control, then hub vortex losses are reduced, but tip region performance may be compromised
Solution Approach 1:
The patent applies local quality by designing the airfoil profile with location-specific characteristics that address the unique flow conditions at different span positions. The hub section features optimized camber distribution to suppress hub vortex formation, while the tip section has different geometric parameters optimized for tip leakage control and maintaining work transfer efficiency, allowing simultaneous optimization of both regions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances turbine efficiency, reduces specific fuel consumption, and lowers cooling flow requirements, resulting in improved performance and cost-effectiveness by optimizing the airfoil loading distribution and mitigating vortex-related losses.
Implementation Method 1
suction surface pressure diffusion
Implementation Method 2
manage Mach numbers
Implementation Method 3
vortex structures
Implementation Method 4
blade loading distributions
Data Source
AI summary
An apparatus and method for an engine component having a working airflow separated into a cooling airflow and a combustion airflow, the engine component comprising a plurality of circumferentially spaced airfoils rotatable about a centerline defining an axial direction, each airfoil comprising an outer wall bounding an interior and defining a pressure side and a suction side extending between a leading edge and a trailing edge to define a chord-wise direction and extending between a root and a tip along a span-wise direction to define a span length; wherein each of the airfoils have an unguided turning angle to stagger angle ratio defined with respect to a percentage of the span length.